Known examples of electrochemical devices, which provide electrical energy through a chemical reaction or which cause a chemical reaction upon input of electrical energy, include various batteries and hydrogen production devices. Polymer electrolyte fuel cells (PEFCs), which are a type of electrochemical device, have the advantage of being operable in a temperature range around ordinary temperature and are promising for use in various fields. Among PEFCs, anion-exchange fuel cells can be more cost-effective since they do not require the use of platinum in an electrode catalyst. As the fuel of an anion-exchange fuel cell there can be used an alcohol-based or hydrazine hydrate-based liquid fuel which is easier to handle than hydrogen and permits reduction in size of the fuel cell system. In particular, hydrazine hydrate is highly reactive and, according to the electricity generation principle, does not produce carbon dioxide. For these reasons, studies employing hydrazine hydrate have been pursued.
Generally, in a PEFC, a cathode catalyst layer is disposed on one side of an electrolyte membrane, and an anode catalyst layer is disposed on the other side of the electrolyte membrane. Such catalyst layers, which may be needed in electrochemical devices, contain an ionomer resin and an electrode catalyst. A typical ionomer resin used in anion-exchange PEFCs is one that has a structure (such as a benzyltrialkylammonium structure) in which an anion-exchange group (a functional group having anionic conductivity) such as a quaternary ammonium group is bonded to a benzene ring via a methylene group (see Patent Literature 1, for example).
The term “ionomer resin” as used herein refers to a resin including an organic compound such as an ion-conductive polymer material, and the term “ionomer solution” as used herein refers to a solution of an ionomer resin dissolved in a solvent.